Atomic-Scale, All Epitaxial In-Plane Gated Donor Quantum Dot in Silicon

Fuhrer, Andreas; Fuchsle, M.; Reusch, T. C. G.; Weber, Bent; Simmons, M. Y.

doi:10.1021/nl803196f

Cited by 109 publications

(107 citation statements)

References 17 publications

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“…Recently significant progress has been demonstrated in experimentally realizing electronic or optoelectronic device structures using single donors or defect centers [1][2][3][4][5][6][7][8][9]. Ion implantation is an industry standard for placing atoms in the near surface region with high precision, for example, for controlled source/drain junctions in silicon complementary metal oxide semiconductor (CMOS) applications.…”

Section: Introductionmentioning

confidence: 99%

Single ion implantation for single donor devices using Geiger mode detectors

Bielejec¹,

Seamons²,

Carroll³

2010

Nanotechnology

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Abstract.Electronic devices that are designed to use the properties of single atoms such as donors or defects have become a reality with recent demonstrations of donor spectroscopy, single photon emission sources, and magnetic imaging using defect centers in diamond. Ion implantation, an industry standard for atom placement in materials, requires augmentation for single ion capability including a method to detect a single ion arrival. Integrating single ion detection techniques with the single donor device construction region allows single ion arrival to be assured. Improving detector sensitivity is linked to improving control over the straggle of the ion as well as providing more flexibility in lay-out integration with the active region of the single donor device construction zone by allowing ion sensing at potentially greater distances. Using a remotely located passively gated single ion Geiger mode avalanche diode (SIGMA) detector we have demonstrated 100% detection efficiency at a distance of >75 m from the center of the collecting junction. This detection efficiency is achieved with sensitivity to ~600 or fewer electron-hole pairs produced by the implanted ion. Ion detectors with this sensitivity and integrated with a thin dielectric, for example 5 nm gate oxide, using low energy Sb implantation would have an end of range straggle of <2.5 nm.Significant reduction in false count probability is, furthermore, achieved by modifying the ion beam set-up to allow for cryogenic operation of the SIGMA detector. Using a detection window of 230 ns at 1 Hz, the probability of a false count was measured as ~10 -1 and 10 -4 for operation temperatures of ~300K and ~77K, respectively. Low temperature operation and reduced false, "dark", counts are critical to achieving high confidence in single ion arrival. For the device performance in this work, the confidence is calculated as a probability of >98% for counting one and only one ion for a false count probability of 10 -4 at an average ion number per gated window of 0.015.

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Section: Introductionmentioning

confidence: 99%

Single ion implantation for single donor devices using Geiger mode detectors

Bielejec¹,

Seamons²,

Carroll³

2010

Nanotechnology

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“…Because of the random nature of dopant diffusion into the channel, we handpicked SATs suitable for our experiment. However, deterministic doping is rapidly emerging as technique that overcomes these kinds of device-to-device variability issues (1,3). Moreover, efforts towards room-temperature quantum effects have been demonstrated in ultrascaled FinFET devices, where the level spacing due to confinement is comparable to the thermal energy at room temperature (41).…”

Section: Methodsmentioning

confidence: 99%

“…There is therefore a world-wide intense research effort aiming at computing at the nano-scale, using both classical and quantum computing approaches (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). These advances are made possible by a complementary effort on building atomic devices and memory (3,(18)(19)(20)(21)(22)(23).…”

mentioning

confidence: 99%

Integrated logic circuits using single-atom transistors

Mol

Verduijn

Levine

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Scaling down the size of computing circuits is about to reach the limitations imposed by the discrete atomic structure of matter. Reducing the power requirements and thereby dissipation of integrated circuits is also essential. New paradigms are needed to sustain the rate of progress that society has become used to. Single-atom transistors, SATs, cascaded in a circuit are proposed as a promising route that is compatible with existing technology. We demonstrate the use of quantum degrees of freedom to perform logic operations in a complementary-metal-oxide-semiconductor device. Each SAT performs multilevel logic by electrically addressing the electronic states of a dopant atom. A single electron transistor decodes the physical multivalued output into the conventional binary output. A robust scalable circuit of two concatenated full adders is reported, where by utilizing charge and quantum degrees of freedom, the functionality of the transistor is pushed far beyond that of a simple switch.cascading full adder | CMOS technology | energy and charge quantization I n digital logic circuits, binary information is encoded by monitoring the current, on vs. off, through a transistor that serves as a switch. This concept has been extremely effectively scaled over the last decades and led to the exceptionally dense and low cost integrated circuits that we use today. Decreasing the physical size of the component transistors has largely enabled the miniaturization. The reduction in the size of conventional transistors will shortly face the barrier that on the subnano length scale matter is discrete. The atomistic nature of matter leads to variability in device characteristics, which is the major problem in device downscaling. As we approach the physical limits of two-dimensional circuits essentially new paradigms are needed to sustain the rate of progress that our society has become used to. Here we utilize the discrete nature of matter at the atomic scale to offer a viable solution. Deterministic doping (1-3) emerges as a technique that overcomes variability problems (4). Furthermore, single atom doping allows for device functionality that exceeds that of a simple switch. This functionality of single-atom transistors, SATs, is robust due to the strong natural confinement of the Coulomb potential of the dopant. We connect the basic units, the SATs, with gain thereby allowing for a scalable circuit. It is because of the nature of SATs that our innovative Si device and experimental design can significantly accelerate the transfer of the new paradigm for device architecture from the laboratory to the R and D department.Increasing integration and logical complexity and shrinking the size and the power requirements of computational networks are key desiderata of current information technology. There is therefore a world-wide intense research effort aiming at computing at the nano-scale, using both classical and quantum computing approaches (5-17). These advances are made possible by a complementary effort on building atomic device...

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“…The SET is operated with a 2.5 mV source-drain bias and has a charging energy of ∼5 meV. Further details of the fabrication methods have been published previously [30]. All data herein were taken inside a dilution refrigerator at 100 mK (electron temperature ∼200 mK).…”

mentioning

confidence: 99%

High-Fidelity Single-Shot Singlet-Triplet Readout of Precision-Placed Donors in Silicon

et al. 2017

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In this work we perform direct single-shot readout of the singlet-triplet states in exchange coupled electrons confined to precision-placed donor atoms in silicon. Our method takes advantage of the large energy splitting given by the Pauli-spin blockaded (2,0) triplet states, from which we can achieve a singleshot readout fidelity of 98.4 AE 0.2%. We measure the triplet-minus relaxation time to be of the order 3 s at 2.5 T and observe its predicted decrease as a function of magnetic field, reaching 0.5 s at 1 T. DOI: 10.1103/PhysRevLett.119.046802 An increased ability to control and manipulate quantum systems is driving the field of quantum computation forward [1][2][3][4]. The spin of a single electron in the solid state has long been utilized in this context [5][6][7][8][9][10][11], providing a superbly clean quantum system with two orthogonal quantum states that can be measured with over 99% fidelity [12]. As a natural next step, the coupling of two electrons at separate sites has been studied in gate-defined quantum dots [5,13,14], as well as in donor systems [15][16][17]. In addition to being the eigenstates for two coupled spins, the singlet-triplet (ST) states of two electrons can form a qubit subspace, and have previously been utilized for quantum information processing [6,[18][19][20][21][22]. Unlike in gate-defined quantum dots, donor systems do not require electrodes to confine electrons. The resulting decrease in physical complexity makes donor nanodevices very appealing for scaling up to many electron sites [15].In the (1,1) charge configuration the ST states are eigenstates if the exchange coupling is greater than any difference in Zeeman energy between the two spins. The singlet and three triplet states are split only by the Zeeman energy in the cases of jT þ i ¼ j↑↑i and jT − i ¼ j↓↓i, and an exchange energy, J, for the singlet jSi ¼ ðj↑↓i − j↓↑iÞ= ffiffi ffi 2 p and jT 0 i ¼ ðj↑↓i þ j↓↑iÞ= ffiffi ffi 2 p states. However, in the (2,0) configuration all triplet states split from the singlet jSð2; 0Þi by a larger exchange interaction, Δ ST , measured in previous works to be > 5 meV for donors [23]. The triplet states are therefore blocked from tunneling from the ð1; 1Þ → ð2; 0Þ charge configuration, known as Pauli spin blockade.Typically, direct ST readout is performed by charge discrimination between the (1,1) and (2,0) states below the ST energy splitting Δ ST . However, this relies on the charge sensor having a large enough differential capacitive coupling to each dot to discriminate between the two charge states. This is not possible in some architectures due to symmetry constraints, in particular, for donors it is advantageous for multiple donor sites to be coupled equally to a charge sensor for independent readout and/or loading. The tightly confined electron wave function at each donor site therefore necessitates that they are equidistant from the charge sensor. As a consequence ð1; 1Þ ↔ ð2; 0Þ charge transfer signals are often too small to detect directly in this architecture.Until now s...

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Atomic-Scale, All Epitaxial In-Plane Gated Donor Quantum Dot in Silicon

Cited by 109 publications

References 17 publications

Single ion implantation for single donor devices using Geiger mode detectors

Single ion implantation for single donor devices using Geiger mode detectors

Integrated logic circuits using single-atom transistors

High-Fidelity Single-Shot Singlet-Triplet Readout of Precision-Placed Donors in Silicon

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